Dividers



J. F. SULLIVAN.-

Dividers.

i w 00 IW UNITED STATES PATENT OFFICE.

JAMES F. SULLIVAN, OF FITOHBURG, MASSACHUSETTS.

DIVIDERS.

SPECIFICATION forming part of Letters Patent No. 225,436, dated March 9, 1880.v Application filed December 15, 1879.

To all whom it may concern Be it known that I, JAMES F. SULLIVAN, of Fitchburg, county of Worcester, State of Massachusetts, have invented an Improvement in Compasses, of which the following description, in connection with the accompanying drawings, is a specification.

My invention relates to compasses or dividers, and is shown embodied in a pair of compasses adapted for machinists or artisans use, for scratching circles on metal, or wood, or other desired material.

In making circles with compasses where any pressure on the pointis necessary, as in scratching on metal or wood, the points are liable to open or separate, thereby destroying the accuracy of the circle. This liability or tendency increases with the increased inclination of the compass-legs from a line at right angles to the surface to be marked. It is desirable, on this and other accounts, thatthe pointed ends of the compasses should be presented as nearly as possible at right angles to the surface to be marked, and at the same time should be held rigid in position. To accomplish this result in accordance with my invention I provide each leg of the compasses below the usual holding-clamp, near their pivoted portion, with a clamping device which permits the marking-points of the compasses to be held securely upon the said legs at any desired distance apart and at any desired angle with re- 7 lation to the surface to be marked.

To enable the points to be readily replaced if broken, I make them detachable, being held in a socket in the legs, the said socket being split and closed firmly upon the shank of the joints by a threaded sleeve.

Figure l is a side viewof a pair of compasses embodying my improvements 5 Fig. 2,

a section through the clamping device or one of the jointed legs, and Fig. 3 longitudinal and cross sections of the point-holding socket.

The compass-legs a b, pivoted at c, are shown as provided with the usual are d, clampingscrew 6, spring 9, and slow-motion screw h. The point-holding portions '6 of the legs are pivoted to the upper or main portions, 61 b, at m, and, as herein shown, are provided each with a slotted are, a, through which passes a clamping-screw, 0, by which the pointportion may be held at any desired angle to the main portion of the leg.

The points r are held in sockets 8, said sockets being split, as shown at t, and screwthreaded on their outside to en gage a threaded sleeve, a, which draws the split ends of the socket together as it is screwed thereon, and

causes them to hold the points r firmly.

A pencil or other desired instrument or tool may be readily inserted and held in the socket s.

I am aware that compasses have been made for drawing with jointed legs; but am not aware of any provided with holding-clamps.

I claim- As a new article of manufacture, a pair of compasses or dividers having its legs jointed, and provided with holding-clamps to maintain the point portion rigidly at any desired angle with the main portions a 1) thereof, substantially as and for the purpose described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JAMES F. SULLIVAN.

Witnesses:

THOMAS J. W001), HENRY J AcKsoN. v 

